Method for detecting image in image detector having edge milled aperture to remove diffraction pattern

Abstract

The present invention relates to an image detecting method of an image detector which processes a shape of an edge of an image input aperture of a 2D image detector which is used in a terahertz band whose frequency is lower than that of infrared light to have a predetermined shape so that a diffraction pattern due to the aperture is not shown in a captured image or a contrast is weakened, thereby obtaining a clear object image with a reduced distortion.

What is claimed is: 
     
         1 . An apparatus for detecting an image by passing an electromagnetic wave, the apparatus comprising:
 an aperture having a predetermined shape to pass an electromagnetic wave,   wherein the aperture is milled such that a transmittance is reduced from an end of an edge of the aperture to a material surface.   
     
     
         2 . The apparatus of  claim 1 , wherein the transmittance is entirely reduced from the end of the edge of the aperture up to a length corresponding to almost one wavelength of the electromagnetic wave. 
     
     
         3 . The apparatus of  claim 1 , wherein the aperture is formed such that the transmittance is entirely reduced from the end of the edge of the aperture to the material surface to have a predetermined gradient. 
     
     
         4 . The apparatus of  claim 1 , wherein the aperture is formed to have a plurality of levels of transmittance which is entirely reduced from the end of the edge of the aperture to the material surface. 
     
     
         5 . The apparatus of  claim 1 , wherein the aperture is formed such that an average of the transmittance is entirely reduced from the end of the edge of the aperture to the material surface. 
     
     
         6 . The apparatus of  claim 1 , wherein the end of the edge of the aperture has a sawtooth shape or irregularities having valleys and mountains. 
     
     
         7 . The apparatus of  claim 1 , wherein intensity distribution of the electromagnetic wave has a gradient from the edge of the aperture to the material surface so that diffraction is removed or reduced. 
     
     
         8 . A method for detecting an image by passing an electromagnetic wave, the method comprising:
 passing an electromagnetic wave through an aperture having a predetermined shape to electromagnetically obtain an image or project the image onto a screen,   wherein the aperture is milled such that a transmittance is reduced from an end of an edge of the aperture to a material surface.   
     
     
         9 . The method of  claim 8 , wherein the transmittance is entirely reduced from the end of the edge of the aperture up to almost one wavelength of the electromagnetic wave. 
     
     
         10 . The method of  claim 8 , wherein the aperture is formed such that the transmittance is entirely reduced from the end of the edge of the aperture to the material surface to have a predetermined gradient. 
     
     
         11 . The method of  claim 8 , wherein the aperture is formed to have a plurality of levels of transmittance which is entirely reduced from the end of the edge of the aperture to the material surface. 
     
     
         12 . The method of  claim 8 , wherein the aperture is formed such that an average of the transmittance is entirely reduced from the end of the edge of the aperture to the material surface. 
     
     
         13 . The method of  claim 8 , wherein the end of the edge of the aperture has a sawtooth shape or irregularities having valleys and mountains. 
     
     
         14 . The method of  claim 8 , wherein intensity distribution of the electromagnetic wave has a gradient from the edge of the aperture to the material surface so that diffraction is removed or reduced.